Hey yall.

I am currently changing out my rockers. I'm going from CompCams Aluminium roller (1.5 NSA w/guideplate) to CompCams Ultra Pro Magnum (1.52 SA wo/guideplate). I installed with about 3/4 turn preload. Starts, idles and revs up smooth and quiet. What is bothering me is only on engine decel (say from a mild 3K blip rev) a noise comes from the rockers, till it gets down in revs.. It almost sounds like a rattle snake..

Has anyone else expierenced something similar to this.. I'm assuming it's the roller tip walking left to right across the valve stem tip, and the NSA tabs on the rocker are hitting the sides of the valve stem.

I'm all ears..

 

Does the car have to be driven to hear it or can you do it sitting in the drive way?

See where I'm going with this?

 

The noise is noticable right in the driveway. I think today ill try to get some audio and post it for everyone to hear.

 

Sounds strange. In general, I have read that the aluminum rockers are more quiet than the steel pro-mags. Since you are going from aluminum to aluminum, and you are certain that are not too tight, might be something else.

Might try 1/2 TPZL or even 1/4 for diagnosis purposes.

 

If I'm not mistaken, the ultra pro mags are chromolly. And if you are correct in saying aluminium rockers are more quiet, it might explain the noticable noise. I am pretty sensitive to sound and smell changes with my car, so the noise kinda freaked me out a lil. I did the ol EOIC preload method, and like I said, it sounds happy running. When I not driving ill update my sig to more correctly reflect the car. Thanks for all the help guys.

 

My bad, you are correct.
I was thinking the new Comp pro aluminums or whatever they are called.

 

What I was going for was for you to take the valve covers off and put oil deflectors on and actually watch what is going on when the sound occurs.

 

I didn't get a chance to record the noise, but I have had the valve covers off while running, and everything is moving so fast that we can't physically see it. I need a high speed camera to record it I guess.. ;p I actually have the car at a friends shop, and had it sitting on the dyno to load test it.. these new rockers have been nothing but trouble, but I guess its my carma catching up. I apologize for not including this info before. The lifters are comp high energy 812's, and the pushrods are 1 piece chromolly.